From 33c3736ec88811b9b6f6ce2cc8967f6b97c3db5e Mon Sep 17 00:00:00 2001 From: Qais Yousef Date: Mon, 23 Mar 2020 13:51:10 +0000 Subject: [PATCH] cpu/hotplug: Hide cpu_up/down() Use separate functions for the device core to bring a CPU up and down. Users outside the device core must use add/remove_cpu() which will take care of extra housekeeping work like keeping sysfs in sync. Make cpu_up/down() static and replace the extra layer of indirection. [ tglx: Removed the extra wrapper functions and adjusted function names ] Signed-off-by: Qais Yousef Signed-off-by: Thomas Gleixner Link: https://lkml.kernel.org/r/20200323135110.30522-18-qais.yousef@arm.com --- drivers/base/cpu.c | 4 ++-- include/linux/cpu.h | 4 ++-- kernel/cpu.c | 42 ++++++++++++++++++++++++++++-------------- 3 files changed, 32 insertions(+), 18 deletions(-) diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c index 6265871a4af2..b93a8f82f215 100644 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -55,7 +55,7 @@ static int cpu_subsys_online(struct device *dev) if (from_nid == NUMA_NO_NODE) return -ENODEV; - ret = cpu_up(cpuid); + ret = cpu_device_up(dev); /* * When hot adding memory to memoryless node and enabling a cpu * on the node, node number of the cpu may internally change. @@ -69,7 +69,7 @@ static int cpu_subsys_online(struct device *dev) static int cpu_subsys_offline(struct device *dev) { - return cpu_down(dev->id); + return cpu_device_down(dev); } void unregister_cpu(struct cpu *cpu) diff --git a/include/linux/cpu.h b/include/linux/cpu.h index 8b295f78da25..9ead281157d3 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -88,8 +88,8 @@ extern ssize_t arch_cpu_release(const char *, size_t); #ifdef CONFIG_SMP extern bool cpuhp_tasks_frozen; -int cpu_up(unsigned int cpu); int add_cpu(unsigned int cpu); +int cpu_device_up(struct device *dev); void notify_cpu_starting(unsigned int cpu); extern void cpu_maps_update_begin(void); extern void cpu_maps_update_done(void); @@ -120,8 +120,8 @@ extern void lockdep_assert_cpus_held(void); extern void cpu_hotplug_disable(void); extern void cpu_hotplug_enable(void); void clear_tasks_mm_cpumask(int cpu); -int cpu_down(unsigned int cpu); int remove_cpu(unsigned int cpu); +int cpu_device_down(struct device *dev); extern void smp_shutdown_nonboot_cpus(unsigned int primary_cpu); #else /* CONFIG_HOTPLUG_CPU */ diff --git a/kernel/cpu.c b/kernel/cpu.c index 4783d811ccf8..30848496cbc7 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -1041,7 +1041,7 @@ static int cpu_down_maps_locked(unsigned int cpu, enum cpuhp_state target) return _cpu_down(cpu, 0, target); } -static int do_cpu_down(unsigned int cpu, enum cpuhp_state target) +static int cpu_down(unsigned int cpu, enum cpuhp_state target) { int err; @@ -1051,11 +1051,18 @@ static int do_cpu_down(unsigned int cpu, enum cpuhp_state target) return err; } -int cpu_down(unsigned int cpu) +/** + * cpu_device_down - Bring down a cpu device + * @dev: Pointer to the cpu device to offline + * + * This function is meant to be used by device core cpu subsystem only. + * + * Other subsystems should use remove_cpu() instead. + */ +int cpu_device_down(struct device *dev) { - return do_cpu_down(cpu, CPUHP_OFFLINE); + return cpu_down(dev->id, CPUHP_OFFLINE); } -EXPORT_SYMBOL(cpu_down); int remove_cpu(unsigned int cpu) { @@ -1178,8 +1185,8 @@ static int _cpu_up(unsigned int cpu, int tasks_frozen, enum cpuhp_state target) } /* - * The caller of do_cpu_up might have raced with another - * caller. Ignore it for now. + * The caller of cpu_up() might have raced with another + * caller. Nothing to do. */ if (st->state >= target) goto out; @@ -1223,7 +1230,7 @@ out: return ret; } -static int do_cpu_up(unsigned int cpu, enum cpuhp_state target) +static int cpu_up(unsigned int cpu, enum cpuhp_state target) { int err = 0; @@ -1257,11 +1264,18 @@ out: return err; } -int cpu_up(unsigned int cpu) +/** + * cpu_device_up - Bring up a cpu device + * @dev: Pointer to the cpu device to online + * + * This function is meant to be used by device core cpu subsystem only. + * + * Other subsystems should use add_cpu() instead. + */ +int cpu_device_up(struct device *dev) { - return do_cpu_up(cpu, CPUHP_ONLINE); + return cpu_up(dev->id, CPUHP_ONLINE); } -EXPORT_SYMBOL_GPL(cpu_up); int add_cpu(unsigned int cpu) { @@ -1289,7 +1303,7 @@ int bringup_hibernate_cpu(unsigned int sleep_cpu) if (!cpu_online(sleep_cpu)) { pr_info("Hibernated on a CPU that is offline! Bringing CPU up.\n"); - ret = cpu_up(sleep_cpu); + ret = cpu_up(sleep_cpu, CPUHP_ONLINE); if (ret) { pr_err("Failed to bring hibernate-CPU up!\n"); return ret; @@ -1306,7 +1320,7 @@ void bringup_nonboot_cpus(unsigned int setup_max_cpus) if (num_online_cpus() >= setup_max_cpus) break; if (!cpu_online(cpu)) - cpu_up(cpu); + cpu_up(cpu, CPUHP_ONLINE); } } @@ -2129,9 +2143,9 @@ static ssize_t write_cpuhp_target(struct device *dev, goto out; if (st->state < target) - ret = do_cpu_up(dev->id, target); + ret = cpu_up(dev->id, target); else - ret = do_cpu_down(dev->id, target); + ret = cpu_down(dev->id, target); out: unlock_device_hotplug(); return ret ? ret : count;